Circuit interrupter



Sept. 29, 1925.

H. G. M DONALD CIRCUIT INTERRUPTER Filed Feb 6. 1922 2 Sheets-Sheet lINVENTOR 29, 1925. I 1,555,299 H.G.MMBONALD C IRCU I T X NTERRUPTERlwllrlllllzlllll INVENTOR Han/0rd G Madam/d. 9 BY 52 dz AT T oRNEYPatented Sept. 29, 1925.

UNITED STATES PATENT" OFFICE.

HOWARD G. MACDONALD, OF IVIURRYSVILLE,v PENNSYLVANIA, ASSIGNOR TO WEST-INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

Application filed February To all whom it may concern:

Be it known that I, Howlnw G. Mac- DONALD, a citizen of the UnitedStates, and a resident of Murrysville, in the county of \Vestmorelandand State of Pennsylvania, have invented a new and useful Improvement inCircuit Int'errupters, of which the following is a specification.

This. inventionrelates to circuit interrupters and particularly to meansfor'extinguishing arcs that are formed during the operation of a circuitbreaker.

My invention has for its objects the provision of means whereby, duringthe opening movement of a circuit breaker, the flow of current throughthe relatively movable contact members is utilized to set up amagneticfield having a powerful blow-out effeet for extinguishing arcswhen the final break occurs, and to simplify and improve generally theapparatus employed for interrupting circuits of high potential.

To enable the invention to be clearly understood, it will be describedwith reference to the accompanying drawings which illustrate theinvention as applied, by way of example, to a single pole double breakoil switch having a movin bridge.

In the drawings, Figure 1 is a sectional elevation of the oil switchconstructed in accordance with my invention.

Fig. 2 is a sectional elevation of the switch in a plane at right anglesto that of Fig. 1.

Fig. 3 is a plan view of the moving bridge of the switch correspondingto Fig. 1, and

Fig. 4 is a diagrammatic perspective view showing the various contactmembers of the switch and also the electrical circuit therethrough whenthe switch is being opened.

In the. drawings, 1 and :2 represent the fixed main contact members ofthe switch. 'lhese contact members are of inverted substantiallyU-shapcd laminated members arranged parallel with one another andpresenting two downwardly directed contact surfaces 3 and 4, in ahorizontal plane. The said U- shaped members are firmly secured, forexample, by means of screws 5 to the undcrsides of metal blocks orcastings (3 which are supported on the terminal rods 7 and 8, the lowerends of which are provided with screw threads and are adapted to engagein screw threaded sockets 9 on the blocks (3. To en- CIRCUITm'rEnRUP'rER.

e, i92 2. Serial No. 534,375.

sure a good electricalcontact' and a firm connection between theterminal rods 7 and 8, and the blocks 6, the sockets 9 may be split, asshown in F1 1,- and clamped on the said terminal r0 s by means-oftangential screws 10. The saidrods 7 and 8 are provided with insulatingbushings or sleeves ll-and pass'up through the main casting or cover 12of the switch, to which cover the said rods may be secured by means ofcement co-operating with a wire bandiu 13 in flanged bushes 14 securedby means 0% bolts 15, or otherwise, in perforations in the casting orcover 12. The terminal rods 7.and 8 which will be provided withterminals'or other conn tions at their upper ends, are arranged inparallel relation with res ct to one another, as shown clearly in 1and2, and for convenience of construction are so switch, although itwill be understood that they may be otherwise disposed.

Stay rods 16 are interposed'between metal seatings 17 on the blocks orcastings .6 (see Figs. 1 and 2), ing square or other shaped heads 20permitting the said plugs .to be externally rotated wardly presentedcontact surfaces 3-and I of the fixed contacts 1 and 2.

The frame 21 is formed with diagonal, parallel or. other cross webs 23(as shown most clearly in Fig. 3). by means of which it is secured tothe lower end 24 of the vertical switch operating rod 25 in such manneras to move in 'a vertical direction 'for closing and opening the switch.

The actuating rod 25 is provided with an extension 26 passing through aguide bushing 27 forming part of or'secured to, the casting or cover 12.'lhe movements required for opening and closing the switch may beimparted to the extension rod 26 by and adjustableiplugs 19 havaccording to a preferred conme plane inclined to the center axis of themeans of actuating mechanisms or solenoids -in an familiar manner, adescription operating means form no part of the present invention.

Two insulating plates 28 are arranged in parallel planes between theterminal rods 7 and 8 and s aced apart a suflicient distance to permittlie switch 0 rating rod to pass therebetween. A vantageousl 'the saidplates are bolted to 'downwar y extend webs 29 integral with, or boltedto,

the un erside of the main casting or switch cover 12 as shownmost-clearly in Fig. 2.

The shunt (if arcing conftactme lxibprs are arranged at t e corners o apara e ogram which is angularly laced with relation to the rectangularbri frame 21. The moving shunt contact members are indicated 2, 33 andand, as clearly shown in T the drawin are secured at .the centers of thesides ofihe frame 21 from which they are separated by insulatingplates-35. The said moving shunt contectmembers advan-.

" tageously com rise copper or brassheaded studs secured means of nuts36 in sockets 37 formed witli lateral portions 38 and secured b means ofset screws 39 to the outer faces 0 the said frame 21, insulatingbushings 40 passing through said lateral per t-ions 38'and surroundingsaid set' screws 89, as shown in detail section in the lower lefthandcorner of Fig. 1. Transverse screws 40a ma be inserted .in tapped holesfrom the un erside of the frame 21 toflock the n said screws 39 inposition.

The fixed shunt contact members which co-operate with, and are adaptedto be engaged by, the above described moving shunt contact members 31 to34 are indicated at ,41, 42, 43 and 44 and are arranged as follows. Twoof the said fixed contact members, namely, 41 and 44, which arediagonally opposite one another, are supported upon the blocks orcastings 6 see Figs. 2 and 4). The said contact mem rs 41 and. 44 arecarried upon rods 45 arranged to slide in brackets 46 attached to, orcast integral with, the blocks or castings 6. Springs 47 are providedupon the rods 45 andthey tend to urge the contact members 41- and 44downwards, split pins or any other form of stops 48 being provided onthe upper ends of the rods 45 to limit the downward movement thereof.The above construction or any other form oflost motionv may be employedin the shunt contact members to ensure their opening after the'maincontact members.

The other diagonally opposite pairs of fixed shunt contact members 42and 43 which co-operate with the moving contact members 32 and 33 areslidably mounted in brackets 49 in an exactly similar manner as are thecontact members 41 and 44 just arci above described. The brackets 49,however, (as shown in Fi 1) are supported between the insulating p ates28 and are secured to the latter by means of belts or screws 50, orotherwise. The said contact members 42 and 43-will thus be completelyinsulated-from any other part of the switch. Flexible conductors 51 maybe provided between the brackets 46 and 49and the contact members 41 to44, respectively, to ensure good electrical connection between thesemembers.

The electricalconnections of. the shunt or contact members are asfollows. The two iagonally opposite fixed contact members 41 and 44are'in electrical connection with the terminal rods 7 and 8 while theother diagonally opposite fixed contact members 42 and 43 carried by theinsulating lstes 28 are electrically connected together jy means of oneor more conductors 52 (see igs. 1 and4) extending from one side of theswitch to the other between said insulating plates, Such conductors 52advantageously comprise wires, strips or flexes of co per protected byinsulating beads ortu (not shown).

The contact members 31 to 34 of the moving shunt contact members carriedby the bridge frame 21 are not diagonally connected but are connected inadjacent pairs, that is to say, the contact member 31 is connested withthe contact member 32 and the contact member 33 with the contact member34. Such connection may advantageously be .provided by means of one ormore W1 strips or flexes 53 of copper protected by insulating beads ortubes 54, as. clearly shown in Fig. 8. The main oil tank of the switchis indicated at 55.

Referring now to Fig. 4, which illustrates the contact members in asomewhat distorted perspective form for the sake of cleai'ness, it willbe seen that the two main breaks of the switch are respectively betweenthe flexible member 1 and the enlargements 22 at the left hand end ofthe bridge frame 21 and between the enlargements 22 at the right handend of the bridge frame 21 and the flexible contact member 2 while, uponopening the switch, the main contact members first separate and after apredetermined movement of the bridge the shunt contact members separate,the circuit then momentarily passing through said shunt contact membersand the four arcs, that is, from the fixed contact member 41, connectedto one terminal rod, to the moving contact member 31 through the arctherebetween, along the conductors 53 to the moving contact member 32thence to the contact member 42 by way of the are between these contactmenr bers, through conductors 52 to contact member 43, then fmm contactmember 43 to contact member 33 by way of the are between these contactmembers, through conductors 53 to contact member 34 and from contactmember 34 to contact member 44 by way of the are between these contactmembers, and thence to the. other terminal rod. Such a circuit isclearly shown in perspective by the dotted line in Fig. 4. 'The circuitthrough the shunt contact members and the four arcs is thusin theform'of two coils or convolutions whereby a strong magnetic field willbe produced with a correspondingly powerful blow-out 'c'tl'ect upon thearcs wluch will thus be quickly extinguished when the final breaksoccur, that is, when the bridge frame 21 has moved down to a sutficientextent.

It will be understood that numerous modifications may be made in theconstruction and disposition of the partsof the switch without departingfrom the scope of'the mvention. For example, although the fixed contactmembers 1 and 2 are provided with two contact surfaces 3 and 4, and aremade flexible by laminations, single contact members of the butter othertype, or more than two breaks, may be employed, the essential feature ofthe invention being that the switch is rovided with shunt or arcing contact mem rs arranged to provide a shunt circuit having a tortuous pathwhen the switch is being opened. It will also be understood that the.invention is not confined in its application to oil switches.

I claim as my invention:

1. In a circuit interrupter, the combination with a plurality ofrelatively movable main contact members, of a plurality of arcingcontact members, a plurality of arcing contact members movable relativeto the firstnamed arcings contact members, and a tortuous electricalconnection between the said relatively movable arcing contact members,whereby a magnetic blow0ut field is set up in the zone therebetween.

2. In a circuit interrupter, the combination with a plurality ofrelatively movable main contact members, of a plurality of relativelymovable arcing contact members having tortuous electrical connectionthere between whereby a magnetic blow-out field is set up.

3. The combinationwith two groups of relatively movable contact members,the contact members of each roup being spaced apart in both longitudinaland transverse directions, of electrical-connections between adjacentcontact members, whereby a path of current is established through thecontact members of the respective groups altermatcly.

'4. In a circuit interrupter, the combination with a. pair of mainstationary cont-act members and a movable bridging member, of a pair ofarcing tips mounted on stationary suports and having electricalconnection to the main contact members, a second pair tact memberssimilarly arranged and 'operate with the first-named of eraing tipsmounted on stationary supports and insulated from the first-named arcingtips but having electrical connection with one another, a pair ofelectricallycounected arcing tips carried by the bridging member andpositioned to engage one tip of each of the first-mentioned two pairs oftips, and a second pair of electrically-com nected arcing tips carriedby the bridging member and positioned to engage the other tip of each ofthe first-mentioned two pairs of tips.

5. In an electric circuit, the combination with a group of four contactmembers arranged m the form of a quadrilateral and a second group ofrelatively movable contioned to co-operatively engage the 'rstnamedgroup, of an electrical connection between two diagonally disposedcontact members of one group and electrical connections between the twocontact members at opposite sides of the other quadrilaterally arrangedgroup. a

6. In an electric circuit, the combination with a. group of spacedcontact members and a second group of spaced relatively movable contactmembers positioned to oo- 7 up, of electrical connections betweendiagonally disposed contact members of one group and an electricalconnection between two conta t members of the other group, one of whichcontact members co-operates with one of the said diagonally disposedmembers.

7. In a circuit breaker, the combinationwith a pair of main contactmembers and a relatively movable bridging member, of a pair of auxiliarycontact members conductively connected to the bridging member, a pair ofcontact members carried upon, and insulated from, the bridging memberand conducti vel y connected to the first said contact membersrespectively, an auxiliary contact member conductively connected to eachof the main contact members for. respectively engaging the first saidauxiliary contact members and a pair of auxiliary CulldUCtiVO-ly-connected contact members for engaging respectively the second pairof auxiliary contact members. 8. In a circuit breaker, the combinationwith a pair of main contact members and a relatively movable bridgingmember, of auxiliary contact members for maintainin the circuit inclosed condition after the bridging member has been disengaged from themain contact members, the contact me bers of one pair of said auxiliarycontact members being insulated from and carried by the main contactmembers and the bridging, member.

5). In a circuit breaker, the combination with a pair of main contactmembers and a. relatively movable bridging member, of

relatively movable auxiliary contact memthe bridging member and allauxiliary 0ons carried by the main contact member tact members beingconnected to constitute "P and the bridging member for maintaining atortuous conductive path whereby a magthe circuit in closed conditionafter the netic blow-out field is set up.

6 bridging member has been disengaged from In testimony whereof, I havehereunto the main contact members. certain of the subscribed my namethis 24th day of Jansa'id auxilia contact members beinginsuuary, 1922.lated from the main contact members and HOWARD G. MACDONALD.

